Built-in antimicrobial plastic resins and methods for making the same
Inventors
LAU, Yiu Ting Richard • KWOK, Sau Kuen Connie • MENG, Wenjun • LI, Sheung Yin • CHEN, Yueying
Assignees
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Publication Number
US-10548314-B2
Publication Date
2020-02-04
Expiration Date
Abstract
A built-in and process-adaptive formulation of antimicrobial commodity thermoplastic resins with mixed compositions comprising of a polymer, a backbone linker, and a non-labile antifouling and biocompatible coupling agent which is melt-processable and enabled to be manufactured into finished products in the form of solid, monolith, tube, composite, fiber, film, sheet and varnish without the prerequisite of biocides or antimicrobial additives is disclosed. The said formulation is adapted to thermoforming and thermal curing processes including but not limited to melt compounding, spinning, extrusion, molding, compression foaming and drawing. The antimicrobial property is attributed to the persistent formation of a non-stick bacteria-repellent tethered layer in which the antifouling component of the said formulation is heterogeneously phase separated and/or surface migrated to the surface after product forming in order to minimize adsorption and/or colonization of bacteria.
Core Innovation
The invention relates to an antimicrobial thermoplastic resin that is biocide-free and has bacterial-repellent properties. The problem addressed is the need for bacterial-repellent and antimicrobial performance without using biocides, while maintaining processing capability and product properties when forming a finished article.
A method is provided in which the biocide-free antimicrobial thermoplastic resin is prepared by melt extruding a masterbatch and a basic plastic selected from polyolefin and polycarbonate. The masterbatch includes a co-polymer structure with polystyrene repeating units combined with polyethylene glycol (PEG), or includes a polypropylene repeating unit combined with PEG, including grafting onto a maleic anhydride-grafted olefin plastomer and polyethylene. The masterbatch is dried and pelletized.
The prepared antimicrobial thermoplastic resin is molded into a finished article through a thermoforming process. Documented materials include antifouling-coupling agent/PEG grafted systems such as SMA-PEG, PP/SMA-PEG, PC/SMA-PEG, PE/SMA-PEG, PP-MA-PEG, PP-MA-C/PEG, and PP-HPM-PEG, with reported characterization including ATR-FTIR, TGA, DSC, melt flow index changes, and phase separated morphology, together with bacterial adhesion/bioburden test results and cytotoxicity/biocompatibility results.
Claims Coverage
The independent claim covers one method for preparing a biocide-free, bacterial-repellent antimicrobial thermoplastic resin with a PEG-containing co-polymer masterbatch, followed by molding via thermoforming into a finished article. The claim includes four inventive features: masterbatch preparation by melt extrusion with a specified co-polymer/PEG structure, drying and pelletizing of the masterbatch, and thermoforming molding into a finished article.
Biocide-free antimicrobial thermoplastic resin with bacterial-repellent properties
Preparing an antimicrobial thermoplastic resin by melt extruding a masterbatch and a basic plastic selected from polyolefin and polycarbonate, wherein the antimicrobial thermoplastic is biocide-free and has bacterial-repellent properties.
PEG-containing co-polymer masterbatch used for melt extrusion
Using a masterbatch comprising a co-polymer comprising a polystyrene repeating unit and a repeating unit represented by PEG (polyethylene glycol), wherein the masterbatch further includes a co-polymer comprising a polypropylene repeating unit and a repeating unit represented by PEG, and/or a polymer comprising a polypropylene repeating unit crosslinked with an agent represented by, and/or a co-polymer comprising a polypropylene repeating unit and a repeating unit prepared by the reaction of a maleic anhydride-grafted olefin plastomer and polyethylene.
Thermoforming molding into a finished article
Molding the antimicrobial thermoplastic resin into a finished article through a thermoforming process.
Drying and pelletizing the masterbatch
Drying the masterbatch; and pelletizing the masterbatch.
Overall, the claim framework ties together a melt-extrusion route using a PEG-containing co-polymer masterbatch, including maleic anhydride-grafted olefin plastomer and polyethylene-based structures, with a biocide-free antimicrobial thermoplastic resin, followed by drying, pelletizing, and thermoforming molding into finished articles.
Stated Advantages
Biocide-free antimicrobial thermoplastic resin with bacterial-repellent properties.
Reduced bacterial adhesion/bioburden as documented by bacterial test results using Escherichia coli and Staphylococcus aureus.
Reported cytotoxicity/biocompatibility as indicated by HaCaT cell viability >90%.
Product-property retention and food-contact compliance, with migration testing for a PP/SMA/PEG/CA variant.
Documented Applications
Thermoforming into finished articles, with documented article forms including solid, monolith, tube, composite, fiber, film, sheet, and varnish.
Antimicrobial/bacterial-repellent performance demonstrated using bacterial adsorption/bioburden challenge tests, including bacterial adhesion/colony count measurements and biofilm-related testing (swab test and spread plating are referenced).
Biocompatibility assessment documented using HaCaT viability (CCK-8) and ISO 10993-5, together with chemical migration tests (EU 10/2011 and US FDA 21 CFR 177.1520) for a PP/SMA/PEG/CA variant.
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